Air induction and tube system for fluid fuel burner



June 5, 1956 R w BECKETT 2,748,843

AIR INDUCTION AND TUBE SYSTEM FOR FLUID FUEL BURNER Filed Oct. 31 1951 2 Sheets-Sheet 1 INVENTOR Reginald T4 Beckett T I BY zflwvwf w ATTORNEYS June 5, 1956 w, BEcKE T 2,748,843

AIR INDUCTION AND TUBE SYSTEM FOR FLUID FUEL BURNER Filed Oct. 31 1951 2 Sheets-Sheet 2 INVENTOR ReginoJ-l VVIBecIrett BY wa ATTORNEYS United States Patent O AIR INDUCTION AND TUBE SYSTEM FOR FLUID FUEL BURNER Reginald W. Beckett, Elyria, Ohio Application October 31, 1951, Serial No. 254,025

9 Claims. (Cl. 158-4) This invention relates to fluid fuel burners, particularly oil burners of the vaporizing type in which oil is forced under pressure through a nozzle to form a spray which mixes with a controlled quantity of forced air to burn in an enclosed combustion chamber. The invention has particular application to the combination of a burner and a heater structure, the latter including a combustion chamber and having an upright wall on which is mounted one of the principal components of the burner. A tube extends between the burner component and the combustion chamber of the heater structure for conducting air into the latter. This tube projects through and is secured to the upright wall of the heater and registers with an air outlet opening in the burner component.

One of the principal objects of the invention is to provide an improved burner component for use in a combination of the character mentioned which burner component includes means for guiding and controlling air admitted into the burner.

Another object is to provide a heater-burner combination of the character mentioned in which the burner includes a housing member disposed in spaced relation to the upright wall of the heater and in which an air controlling cowl or hood is interposed between the housing and the heater wall. In a specialized version of this aspect of the invention the cowl or hood takes the form of a U-shaped member, preferably separable from the burner housing, arranged for direct connection to the heater wall to serve as an attaching means for securing the burner component to the heater.

Another object is to provide an air controlling cowl or hood which serves as a supporting member for the burner of a heater-burner combination and which also incorporates a movable air controlling gate for regulating the admission of air to the burner component.

Another object is to provide a heater-burner combination in which the principal burner component is supported on the heater by an air controlling hood or cowl having a downwardly directed air admitting opening above and in confronting relation to the tube which conducts air from the burner component into the combustion chamber of the heater so that air entering the burner component through the hood opening is drawn over the air tube.

Another object is to provide, for use in a heater-burner combination of the character mentioned, an improved construction of air tube and heater wall in which the heater wall is formed with an opening for the air tube, the opening being appreciably larger than the air tube to eliminate close tolerances in manufacture and to facilitate assembly and in which the air tube carries or is formed with specialized locating means for positioning or centering the air tube in the heater wall opening. More specifically, it is sought to provide an air tubeheater wall arrangement in which the air tube is formed with circumferentially spaced elements such as ribs that 70 provide both radial and longitudinal locating surfaces or shoulders for engagement with the outer face of the heater wall and the surface of the tube receiving opening in the latter.

Other objects and advantages pertaining to novel and useful combinations and arrangementsof parts and certain features of design and construction are set forth in the following detailed description of the invention made in connection with the accompanying drawings forming a part of the specification.

In the drawings: v

Figure l is a fragmentary vertical section, partly diagrammatic, through a portion of a heater-burner combination structure, partly in section and with parts broken away and removed, showing the burner component in withdrawn or spaced relation to the heater structure and in position to be mounted on the latter;

Fig. 2 is a view similar to Fig. 1 showing the burner component and heater structure in assembled relation, the burner component being mounted on and wholly supported by the upright wall of the heater;

Fig. 3 is an elevational view of the burner component taken substantially along the line indicated at 3-3 of Fig. 1 and enlarged with respect to that figure;

Fig. 4 is a sectional detail showing the mounting and holding means for the air controlling gate, this view being taken substantially along the line indicated at 4'4 of Fig. 2 and enlarged with respect to that figure; and

Fig. 5 is an elevational view, partly diagrammatic and to the same scale as Fig. 3, showing a portion of the upright heater wall, this view being taken substantially along the line indicated at 55 of Fig. l. e r

The device of the present invention is embodied in the combination of a heater structure A and a burner component B adapted for support in demountable relation on upright wall 1 of the heater structure.-- Reference is made to copending application for patent Serial No. 24,559, filed May 1, 1948, for Oil Burner of the 'Atomizing Type, now United States Patent 2,599,153, and-copendingapplication for patent Serial No. 152,353, filed March 28, 1950, for Convertible Fluid Fuel Burner, which describe and claim related inventions. The heater structure is essentially conventional and may take any of several forms such as a hot air furnace or a steam or water boiler, the latter being illustrated. A combustion chamber indicated at C is defined by a refractory floor 2 and walls 3, the space between the combustion chamber walls and the cast iron or other metal wall 1 receiving suitable loose fill insulating material 4. The water to be heated is contained in cells or boiler sections one of which is indicated at 5. A locating flange 6 may be secured to or cast integrally with the heavy sectioned metal heater wall 1 and is received under the arch of the boiler section 5.

Extending through circular opening 7 in the heater wall is an air tube assembly which may be of one piece cast construction or, as shown, may comprise a base ring 8 and a cast metal head structure 9 received telescopically in interfitting relation on the opposite ends of a cylindrical steel or other metal tube 10. The head 9 may include separable partsa flanged ring secured on tube 10 and a mating tubular extension which is received in an opening in the refractory wall 3 of the combustion chamber. A circular flange 11 on one end of the tubular portion of the head is received against and secured to a similar circular flange 12 on the ring carried by the tube 10, screws or other suitable fasteners, not shown, being used to secure the parts together.

The opening 7 formed in the heater wall 1 to receive the air tube assembly is considerably larger than the air tube eliminating the necessity of maintaining close toler ances or performing costly machining operations in manufacture. While the space or clearance 13 between the air tube and the walls of the opening 7 is not held to a precise 3 dimension and is not critical, it is preferably at least sufl'tciently large to pass the flanges 11 and 12 of the burner head 9 so that the complete air tube can be inserted through the opening in assembly.

The base ring 8, cast of metal such as iron, is formed at its air receiving end that registers with an opening in the burner housing with a cylindrical portion larger in diameter than the steel tube 10. A tapered or frusto-conical portion of the base ring connects the cylindrical portion to the steel tube. On the outside of the base ring, elements such as longitudinal ribs 14 secured to or cast integrally with the ring serve to locate and center the air tube in the wall opening 7. The ribs are notched at that end of the base ring which receives the steel tube 10, permitting end portions of the ribs or elements to be received within the walls of the wall opening 7 and providing radial shoulders 15 which bear against the outer face of the heater wall to locate the air tube axially with respect to the heater. The portions of the ribs received within the wall opening 7 are cast or trimmed as by grinding or filing to a diameter such as to provide an easy sliding fit in the opening.

At its outer or air receiving end, the base ring 8 is formed with a circumferentially extending radial flange 20 through which extend a plurality of fasteners such as screws 16 threaded into thick sectioned portions 17 of the heater wall 1 surrounding the opening 7. Reliefs 18 are formed in outer face 21 of the head flange 20 to accommodate heads 19 of the fasteners 16 thereby recessing the screw heads and permitting the end face 21 of the base ring to abut the burner housing, as will later appear.

The air tube structure, although generally considered part of the fluid fuel burner, is thus adapted for assembly with or installation in the heater structure so that the air tube can be shipped in commerce and installed with the heater structure. This permits accurate positioning and alignment of parts by the manufacturer of the heater structure to insure, for example, that the end of the burner head 9 on the air tube is flush with the inside face of the combustion chamber walls and that material such as refractory cement 23 used to seal the burner head in the wall of the combustion chamber is properly placed, trimmed and is free of cracks.

Economy of manufacture is realized since the base ring 8 and the burner head 9 of the air tube as well as the wall 1 of the heater structure can all be inexpensive sand castings requiring little or no machining. By reason of the ample clearance in the opening 7 about the air tube, these parts need not be held to close tolerances. The locating of the air tube longitudinally with respect to the heater wall is accomplished by the shoulders 15 provided by the notches on the ribs 14. While finish machining of the notches and shoulders 15 on the ribs 14 is usually unnecessary, it is feasible, when adjustment is desired, to face the shoulders by simple grinding or filing operations. The distance between the heater wall and the end face 21 of the air tube base ring as well as the alignment of the air tube and its registry with the opening in the burner housing can thus be readily altered to suit the needs of any particular assembly.

The removable burner component B and the air tube carried by the heater together comprise a complete burner. The removable component comprises a main housing or hollow body member 25 which may be of cast iron or cast aluminum. The interior of the housing is divided by integral partition means 26 to provide the usual fan scroll chamber 27 and plenum or air chamber 28. An internal passage connects the chambers so that air drawn into the upper fan scroll chamber through circular opening 29 in wall 30 of the housing by fan 31 is forced tangentially into the lower air chamber 28. A circular opening 32 in the housing wall 30 registers with the opening in the base ring 8 of the air tube assembly and is continuous with the air chamber 28 so that air forced into the latter by the fan 31 is discharged into the air tube and flows spirally through the latter.

The fan 31 is mounted on the shaft of an electrical motor 34 having a flanged base 36 received against the outer or rear wall 35 of the burner housing. The motor shaft extends through a suitable opening in the housing wall 35 and the flanged base of the motor is secured to the housing as by cap screws 37.

An assembly comprising a fuel supply conduit 38 and ignition electrodes 39 extends longitudinally through the burner housing air chamber 28 and the air tube. The electrodes and fuel conduit are secured in a clamp bracket 40 having an angularly disposed foot portion fastened to the bottom of the housing by a captive bolt or cap screw 41. A spider 42 secured on the fuel conduit 38 adjacent nozzle 43 has radial arms with ends disposed to slide on the inside walls of the air tube 10 to thereby center the fuel conduit in the air tube. Oil or other fuel is supplied to the conduit 38 and nozzle 43 through a bendable metal tube 44 which is connected to a conventional pump (not shown) and suitable source of supply.

An ignition transformer 46 mounted on the housing wall 35 has secondary terminals 47 which project into the air chamber 28 through an opening or openings in the wall 35. The terminals contact resilient metal conductors or springs 48 carried by the ends of the electrodes 39.

Serving as an attachment device or mounting bracket and also as a guide for air drawn into the fan chamber 27 is a hood or cowl 50. This cowl or hood device normally forms a part of the removable burner component, serves as a spacing and supporting device, and defines an air induction or entry passage in which is located a flow control gate. It may be cast integrally with the housing 25 or, as shown, may comprise a separate U-shaped casting disposed in inverted position in the air entry space between the housing and the heater wall. Inwardly directed ears 51 along one edge are disposed flatwise against the front wall 30 of the housing. Cap screws 52 extend through the ears and are threadtd into tapered holes in the housing. The cowl or hood presents a downwardly directed opening 53 directly above the base ring 8 of the air tube so that air drawn into the burner by the fan 31 is caused to flow over the air tube base producing a beneficial cooling of the metal parts and heating of the air. The oppositely directed edges of the hood 50 are disposed in parallel planes and are abutted against the confronting spaced parallel walls of the burner housing and the heater wall, edge 55 of the hood being disposed against the face of the housing wall 30 while edge 56 is abutted against the outer face of the heater wall 1.

Recesses 57 formed one on each side of the hood receive bosses 58 cast integrally on the heater wall 1. The closely interfitting relation of the bosses in the recesses serves to locate the burner component in correct predetermined relation to the heater wall and to support the weight of the burner component. Studs 59 secured in the bosses 58 are received through openings in integral flanges 60 that surround the recesses 57 and the parts are drawn and held together by nuts 61 screwed onto the studs 59.

As shown in Fig. 2 the dimensions of the air tube base ring 8 and the cowl 50 are such that when the burner component is suspended on the studs 59 the air tube base ring acts as a spacer between the heater wall and the housing. The air tube flange 20 seats against the front wall 30 of the housing and the opening in the air tubc base registers with the outlet or discharge opening 32 from the air chamber 28. In connection with this aspect of the disclosure reference is made to my copending application for United States Patent Serial No. 152,353 filed March 28, 1950, entitled Convertible Fluid Fuel Burner. The cowl 50 has opposite edges which sealingly engage the housing wall and the upright wall 1 of the heater to enclose a portion of the space therebetween in the provision of an air entry passage and to restrict air drawn into the burner through the inlet opening 29 to flow upwardly into the hood through the bottom entry opening 53.

A gate 63 for regulating or controlling the flow of air through the entry is mounted within the hood 50 to turn about a horizontal axis adjacent one of its edges. The

gate is formed of sheet metal and at one end has an angularly disposed ear 64 that is apertured to receive a reduced diameter end on supporting pivot pin 65. This pin is screwed through a tapped hole in the lower end of one of the hood side walls. A lock nut 66 holds the pivot pin in adjusted position. The shoulder provided on the pin by the reduced diameter end portion abuts the ear to locate the air gate and to resist endwise movement. At its end opposite the supporting ear 64 the air gate is secured as by welding or brazing to a square sectioned portion 67 of a stub shaft that is journaled in a drill hole in the lower portion of the hood side. The shaft has a circular sectioned end portion that extends through the journal hole in the hood and on the outside of the latter is threaded to receive an adjusting arm or lever 69. A pair of spring washers 70 and 71 are received on the circular sectioned portion 68 of the stub shaft on opposite sides of the hood Wall and are confined and compressed between the adjusting arm 69 and a shoulder 72 formed on the stub shaft at the end of the square sectioned portion 67. The spring Washers are thus pressed against opposite faces of the wall of the hood and exert frictional restraint on turning of the air gate 63 while the latter is being adjusted to the proper opening. A set screw 73 screwed into the adjusting arm 69 engages the shaft portion 68 to prevent turning of the adjusting arm on the latter and a set screw 74 threaded through the end of the arm 69 is tightened against the outside face of the hood wall to lock the arm and the gate 63 in adjusted position. As an alternative arrangement, the spring washers 7i) and 71 are omitted and the locking set screw 74 is backed off or removed to permit the air gate to turn freely on the pivot pin 65, the shaft portion 68 likewise turning freely in the hood journal. In this free turning or swinging arrangement, the air gate is moved to open position by air pressure when the fan 31 is driven by the motor. When the fan is stopped the air pressure is reduced and the air gate drops by gravity against a positioning lug or stop 75 which may take the form of a boss cast integrally on the inside of the hood 50 at the lower end of one of the side walls of the latter. In this free turning arrangement, the movement of the air gate to closed position against the stop 75 prevents or retards the gravity flow of air through the burner. During the shutdown period following each period of operation of the burner, cooling of the heater is reduced and the effectiveness and efliciency of the heating installation is increased.

The installation of burner-heater combinations in homes and other buildings is greatly facilitated by the present invention. The air tube assembly is installed in the heater structure by the manufacturer of the heater under factory controlled conditions. The heater, including the air tube assembly, is then shipped to and installed at the place where it is to be used. The burner com- 'ponent, a relatively delicate and more easily damaged item, is separately shipped, usually at a later date, and assembled with the heater at the site of use. In this assembling operation, the fuel conduit 38 and the electrodes 39 are conveniently secured to the burner housing 25 as a unit assembly, the bolt or screw 41 being used for this purpose. The assembly of the burner component and the heater structure is then effected by positioning the parts in alignment and feeding the fuel conduit-electrode assembly into the air tube as shown in Fig. l. The hood recesses 57 are placed in mating relation over the supporting bosses 48 on the heater wall 1. With the weight of the burner component thus carried by the heater bosses, the retaining nuts 61 are easily applied to the studs 59.

' 6 The burner is then operated and adjusted in the 'usual manner. I

'In accordance with the patent statutes the principles of the present invention may be utilized in various ways, numerous modifications and alterations being contemplated, substitution of parts and changes in construction being resorted to as desired, it being understood that'the apparatus shown in the drawings and described above is given merely for purposes of explanation and illustration without intending to limit the scope ofthe claims to the specific details disclosed. a

What I claim and desire to secure by Letters Patent of the United States is: 1 t a a 1. ha heater-burner combination of the character described, a heater structure comprising means defining a combustion chamber and a wall spaced from the chamher, a burner component mounted on the structure for facile removal and replacement as a unit, and-an airtube wholly supported by the heater structure substantially independently of the burner component and extending between the combustion chamber and the unit burner component, the unit burner component including a housing having connected internal fan and air chambers and a wall disposed in spaced relation to the heater wall, the housing wall being formed with openings one of which places the fan chamber in communication with the space between the walls to receive air from such space, the air tube including a base portion interposed as a spacer between the heater wall and the housing wall and having a through passage in registry with another of the housing wall openings thereby placing the air tube in communication with the air chamber, said base portion of the air tube being formed with axially extending integral ribs having ends received abuttingly against the wall of the heater structure, means extending between the heater structure and the housing for locating and supporting the unit burner component as a cantilever and in predetermined relation to the heater wall and for facile removal and replacement independently of the air tube, means retaining the air tube in fixed supported relation to the heater structure during such removal and replacement of the unit burner component, a fan in the fan chamber, means supported by the housing and removable therewith as part of the unit burner component for actuating the fan to draw air into the fan chamber from the space between the housing and the heater wall and to force such indrawn air into the air chamber and thence into and through the air tube, and means for supplying fluid fuel to air so forced through the air tube to form a combustible mixture to be burned in the combustion chamber of the heater.

2. A heater-burner combination comprising heater structure including a supporting Wall formed with an opening, a burner component mounted on the wall in spaced confronting relation to the opening, and an air tube extending through the wall opening, said air tube comprising an annular end portion disposed against the burner component and located in the space between the burner component and the wall of the heater structure and formed with circumferentially spaced ribs, said ribs being notched to provide locating surfaces received within the opening in the Wall to center the tube in the opening and shoulders received against the wall to locate the tube longitudinally with respect to the wall.

3. In combination in a heating device of the type comprising a heater component having means defining an internal combustion chamber and an upright wall spaced from the combustion chamber, the heater Wall being formed with an aperture to receive an air tube, a burner component comprising a hollow housing formed with an internal fan chamber, the housing having a wall disposed in spaced confronting relation to the upright wall of the heater structure and formed with an air inlet opening communicating with the fan chamber, the housing also having an air outlet opening communicating with the fan chamber, a fan in said fan chamber, a motor mounted on and wholly supported by the housing, said motor being drivingly connected to the fan to actuate the latter to draw air into the fan chamber through said inlet opening and to release such air through the outlet opening, an air tube registered with the outlet opening and wholly supported by the heater component independently of the burner component, said air tube extending through the heater wall aperture to the combustion chamber to receive air released from the outlet opening and carry such air to the combustion chamber, a separate hood with imperforate top and side portions joined together in the form of a normally inverted U, interposed between and substantially sealingly engaging the confronting housing and heater component walls all along the lengths of the top and side portions of the hood to define an air induction chamber between the walls and continuous with the housing air inlet opening, said hood being formed to provide a downwardly directed air opening between the lower ends of the side portions which constitutes the sole entry for air flowing into the induction chamber, means detachably securing the hood to the burner housing, means detachably securing the hood to the heater component wall for facile removal and replacement whereby the hood constitutes an attaching and spacing bracket for mounting the burner housing on the heater component wall, the burner housing and the hood secured thereto, together with the fan and the actuating motor being removable from and replaceable on the heater component wall as a unit with the air tube remaining undisturbed and independently supported by the heater component, and means for supplying fuel to air carried to the combustion chamher.

4. In combination in a heating device of the type comprising a heater component having means defining an internal combustion chamber and an upright wall spaced from the combustion chamber, the heater wall being formed with an aperture to receive an air tube, a burner component comprising a hollow housing formed with an internal fan chamber, the housing having a wall disposed in spaced confronting relation to the upright wall of the heater structure and formed with an air inlet opening communicating with the fan chamber, the housing also having an air outlet opening communicating with the fan chamber, a fan in said fan chamber, a motor mounted on and wholly supported by the housing, said motor being drivingly connected to the fan to actuate the latter to draw air into the fan chamber through said inlet opening and to release such air through the outlet opening, a separate hood comprising horizontally spaced imperforate side wall elements and an imperforate top wall element interposed between the confronting housing and heater component walls, said top wall element joining the upper ends of the spaced side wall elements, whereby to provide an air induction chamber defined by the spaced confronting walls and by the wall elements of the hood, the housing outlet opening being wholly below the hood, the lower edges of the hood side wall elements defining a horizontal air entry opening above such outlet, said entry and inlet openings being the sole openings through which air enters and leaves the induction chamber, an air tube centered beneath and located wholly below the level of the horizontal air entry opening, said air tube having one end registered with the air outlet opening and extending through the heater wall aperture to the combustion chamber, whereby all the air that flows into the fan chamber through the inlet opening first fiows upwardly into the induction chamber through said horizontal entry opening and induces an air flow about said one end of the air tube, and means for supplying fuel to the combustion chamber.

5. In combination in a heating device of the type comprising a heater component having means defining an internal combustion chamber and an upright wall spaced from the combustion chamber, the heater wall being formed with an aperture to receive an air tube, a burner component comprising a hollow housing formed with an internal fan chamber, the housing having a wall disposed in spaced confronting relation to the upright wall of the heater structure and formed with an air inlet opening communicating with the fan chamber, the housing also having an air outlet opening communicating with the fan chamber, a fan in said fan chamber, a motor mounted on and wholly supported by the housing, said motor being drivingly connected to the fan to actuate the latter to draw air into the fan chamber through said inlet opening and to release such air through the outlet opening, an air tube registered with the outlet opening and wholly supported by the heater component independently of the burner component, said air tube extending through the heater wall aperture to the combustion chamber to receive air released from the outlet opening and carry such air to the combustion chamber, a hood interposed between the confronting walls to control the flow of air into the fan chamber, said hood having top and side element portions each with oppositely directed edges respectively abutted against the housing wall and the heater wall and defining an air entry passage between the confronting walls and continuous with the air inlet opening, means detachably securing the hood to the burner housing, means detachably securing the hood to the heater component wall for facile removal and replacement whereby the hood constitutes an attaching and spacing bracket for mounting the burner housing on the heater component wall, the burner housing and the hood secured thereto, together with the fan and the actuating motor being removable from and replaceable on the heater component wall as a unit with the air tube remaining undisturbed and independently supported by the heater component, and means for supplying fuel to air carried to the combustion chamber.

6. In combination in a heating device of the type comprising a heater component having means defining an internal combustion chamber and an upright wall spaced from the combustion chamber, the heater wall being formed with an aperture to receive an air tube, a burner component comprising a hollow housing formed with an internal fan chamber, the housing having a wall disposed in spaced confronting relation to the upright wall of the heater structure and formed with an air inlet opening communicating with the fan chamber, the housing also having an air outlet opening communicating with the fan chamber, a fan in said fan chamber, a motor mounted on and wholly supported by the housing, said motor being drivingly connected to the fan to actuate the latter to draw air into the fan chamber through said inlet opening and to release such air through the outlet opening, a separate hood comprising horizontally spaced imperforate side wall elements and an imperforate top wall element interposed between the confronting housing and heater component walls, said top wall element joining the upper ends of the spaced side wall elements, whereby to provide an air induction chamber defined by the spaced confronting walls and by the wall elements of the hood, the housing outlet opening being wholly below the hood, the lower edges of the hood side wall elements defining a horizontal air entry opening above such outlet, said entry and inlet openings being the sole openings through which air enters and leaves the induction chamber, an air tube centered beneath and located wholly below the level of the horizontal air entry opening, said air tube having one end registered with the air outlet opening and extending through the heater wall aperture to the combustion chamber, whereby all the air that flows into the fan chamber through the inlet opening first flows upwardly into the induction chamber through said horizontal entry opening and induces an air flow about said one end of the air tube, a gate connected to and supported solely by the side wall elements of the hood for pivotal movement to and from a closed position across 9 the air entry opening to control the flow of air 'intothe induction chamber, and means for supplying fuel to the combustion chamber.

7. In combination in a heating device of the type comprising a heater component having means defining an internal combustion chamber and an upright wall spaced from the combustion chamber, the heater wall being formed with an aperture to receive an air tube, a burner component comprising a hollow housing formed with an internal fan chamber, the housing having a wall disposed in spaced confronting relation to the upright wall of the heater structure and formed with an air inlet opening communicating with the fan chamber, the housing also having an air outlet opening communicating with the fan chamber, a fan in said fan chamber, a motor mounted on and wholly supported by the housing, said motor being drivingly connected to the fan to actuate the latter to draw air into the fan chamber through said inlet opening and to release such air through the outlet opening, a separate hood comprising horizontally spaced imperforate side wall elements and an imperforate top wall element interposed between the confronting housing and heater component walls, said top wall element joining the upper ends of the spaced side wall elements, whereby to provide an air induction chamber defined by the spaced confronting walls and by the wall elements of the hood, the housing outlet opening being wholly below the hood, the lower edges of the hood side wall elements defining a horizontal air entry opening above such outlet, said entry and inlet openings being the sole openings through which air enters and leaves the induction chamber, an air tube centered beneath and located wholly below the level of the horizontal air entry opening, said air tube having one end registered with the air outlet opening and extending through the heater wall aperture to the combustion chamber, whereby all the air that flows into the fan chamber through the inlet opening first flows upwardly into the induction chamber through said horizontal entry opening and induces an air flow about said one end of the air tube, flange means on the inside of the hood, fasteners connecting the inside flange means to the housing to secure the hood and the housing together, such fasteners normally being concealed by the hood in the assembled combination heating device, flange means on the outside of the hood, separable fasteners connecting the outside flange means to the wall of the heater component, said last mentioned fasteners being visible and accessible in the assembled combination, whereby the hood constitutes an attaching bracket mounting the burner component on the heater component wall for facile removal and replacement, and means for supplying fuel to the combustion chamber.

8. In combination in a heating device of the type comprising a heater component having means defining an internal combustion chamber and an upright wall spaced from the combustion chamber, the heater wall being formed with an aperture to receive an air tube, a burner component comprising a hollow housing formed with an internal fan chamber, the housing having a wall disposed in spaced confronting relation to the upright wall of the heater structure and formed with an air inlet opening communicating with the fan chamber, the housing also having an air outlet opening communicating with the fan chamber, a fan in said fan chamber, a motor mounted on and wholly supported by the housing, said motor being drivingly connected to the fan to actuate the latter to draw air into the fan chamber through said inlet opening and to release such air through the outlet opening, a tube extending through the heater wall aperture and defining a passage for conducting air from the housing to the combustion chamber, said air tube having a base portion formed with an end opening registered with the air outlet opening of the housing, said base portion of the air tube having an end face locatingly abutted against the housing, said air tube base portion being formed with radial shoulder means located in a plane spaced from and generally parallel to the end face of the tube base portion, said shoulder means being oppositely directed from such end face and locatingly abutted against the heater component Wall whereby the base portion of the air tube constitutes a first spacer between the housing and the heater wall, a hood interposed between the confronting walls to control the flow of air into the fan chamber, said hood having top and side element portions each with oppositely directed edges respectively abutted against the housing wall and the heater wall and defining an air entry passage between the confronting walls and con tinuous with the air inlet opening, said hood constituting a second spacer between the housing and the heater wall wholly independent of and separated from said first spacer, and means for supplying fuel to air conducted to the combustion chamber.

9. In combination in a heating device of the type comprising a heater component having means defining an internal combustion chamber and an upright wall spaced from the combustion chamber, the heater wall being formed with an aperture to receive an air tube, a burner component comprising a hollow housing formed with an internal fan chamber, the housing having a wall disposed in spaced confronting relation to the upright wall of the heater structure and formed with an air inlet opening communicating with the fan chamber, the housing also having an air outlet opening communicating with the fan chamber, a fan in said fan chamber, a motor mounted on and wholly supported by the housing, said motor being drivingly connected to the fan to actuate the latter to draw air into the fan chamber through said inlet opening and to release such air through the outlet opening, a tube extending through the heater wall aperture and defining a passage for conducting air from the housing to the combustion chamber, said air tube haivng a base portion formed with an end opening registered with the air outlet opening of the housing, said base portion of the air tube having an end face locatingly abutted against the housing, said air tube base portion being formed with radial shoulder means located in a plane spaced from and generally parallel to the end face of the tube base portion, said shoulder means being oppositely directed from such end face and locatingly abutted against the heater component wall whereby the base portion of the air tube constitutes a first spacer between the housing and the heater wall, a hood interposed between the confronting walls to control the flow of air into the fan chamber, said hood having top and side element portions each with oppositely directed edges respectively abutted against the housing wall and the heater wall and defining an air entry passage between the confronting walls and continuous with the air inlet opening, said hood constituting a second spacer between the housing and the heater wall wholly independent of and separated from said first spacer, means securing the hood to the burner housing, means detachably securing the hood to the heater component wall for facile removal and replacement whereby the hood also constitutes a bracket for attaching the burner housing to the heater component wall, the air tube being secured to and wholly supported by the heater component independently of the burner component, the burner housing and the hood secured thereto, together with the fan and the actuating motor, being removable from and replaceable on the heater component wall as a unit with the air tube supported independently of the burner component whereby such air tube remains secured to the heater component 1 1 wall and undisturbed during such removal and 'replace- 2,310,274 ment of the burner housing unit, and means for supplying ,3 9 fuel to air conducted to the combustion chamber. 2,546,409 2,599,153 References Cited in the file of this patent 5 UNITED STATES PATENTS 2,000,733 Avery May 7, 1935 12 Beckett Feb. 9, 1943 Beckett Sept. 28, 1943 Ritter Mar. 27, 1951 Beckett June 3, 1952 

